Progressive inspections: splitting the annual into phases

Instead of one large inspection every twelve months, a progressive inspection program divides the required work into phases carried out at regular intervals. Over one cycle, the aircraft receives the full scope. In exchange, it is available most of the year — provided the program exists on paper and every phase is actually done on time.

What the idea is

• The inspection scope is split into defined phases: for example a structure phase, an engine phase, an avionics and electrical phase, and a records and AD phase.
• Each phase is performed on a fixed interval, in hours or in calendar time, and is signed off like an inspection event.
• At the end of the cycle the aircraft has been inspected across its whole scope, with a paper trail for every part of it.
• Findings discovered in one phase are handled then, rather than all at once at the end of the year.

When it pays off

• Aircraft with high utilisation: flight school airplanes, rental aircraft, aircraft used for aerial work.
• Aircraft where a week out of service costs more than the inspection itself: a tow plane, a pipeline patrol tail, an air ambulance.
• Owners who would rather fix a small finding now than stack ten findings for the annual.

When it is not worth it

• A low-time tail that flies forty hours a year: the annual is cheap relative to the administration you would be taking on.
• A single owner who will not maintain the tracking, or an aircraft whose ownership may change soon — handing over a program mid-cycle is friction in a sale.
• A situation where no shop is willing to stand behind the program on a predictable schedule.

What you have to get right

1. 1Write the phases with real scope, not labels. Each phase must state what is inspected and what is signed.
2. 2Choose intervals that match how the aircraft is actually flown, and that the shop can honour in a busy season.
3. 3Decide in advance what happens when a phase is late: a grace allowance, or an immediate return to the annual requirement.
4. 4Keep the phase records as inspection entries with the same rigour as an annual — a missing phase is a missing inspection.
5. 5Review the program every year with the people who run it, and update it when the aircraft changes: new avionics, new engine, new use.

Leaving the program

• Decide the exit rule before you need it: what has to be completed before the aircraft returns to a 12-month annual, and who signs that statement.
• Make sure the record explains which phases were performed and when, so the next owner or inspector can see the aircraft's true condition.
• If you sell, disclose the program status early. A buyer's mechanic will ask, and a clean hand-over is a selling point.